Lower unit for outboard motors



May 5v, 1936. F, T |RGEN$ 2,039,535

LOWER UNIT `EOR OUTBOARD MOTORS Filed June 2, 1934 2 Sheets-Sheet 1 4/ 47 Inkt/1i 38 4Q 4 50 45 37M" l 1 3/ F7' ,z z J9 ,agi J Z0 .Z5 ZZ z3 /4 5 /0 INVENTOR wm 1fA .95? BY vnf/ www ATTORNEYS May 5, 1936. F. T. IRGx-:Ns

LOWER UNIT FOR OUTBOARD MOTORS Filed June 2, 1934 2 Sheets-Sheet 2 M 2,4 wMV ATTORNEYS Patented May 5, 19,36

LOWR UNIT FOR OUTBOARD MOTORS Finn T. Irgens, Wauwatosa, Wis.. assignor rto Outboard Motors` Corporation, `Milwaukee.v Wis., a corporation of Michigan Application :une z, 1934, sensi No. '128,845 s calm. ictus-1r)LL This invention relates to improvements in lower units for outboard motors. Itis the object ofthe invention to provide a novel and improved lower unit structure which, in the quantities in which outboard motors are produced, can be made more economicallythrough the use of die casting than wouldxbe possible either in the conventional sand casting methods or in'the often-proposed resort to stampings. As

compared with a stamped lower unit, the device herein disclosed will have more bocLv and strength and be more economical of manufacture. As compared with a sand cast lower unit the device herein disclosed will be extremelyflight and economical of manufacture.

It is a further object of the invention to provide a die c'ast lower unit wherein yvarious diecast parts are assembled upon a conventionally drawn tubular shaft housing in a novel and inexpensive manner. i

In the drawings:

Figure 1 is a vertical axial section through the lower unit portion of an outboard motor which embodies the invention. l v

Figure 2 is a view in side elevation, of the several component parts employed in the device illustrated in Figure 1. f

Figure 3 is a view taken in-section in the plane indicated at 3 3 in Figure 1. A

Figure 4 is a view showing in vertical transverse section the component parts of a lower unit com prising a modified embodiment of the invention.- Figure 5 is a side elevation of the interior face f of one of theA parts shown in Figure 4.

Figure 6 is a plan view of the parts shown in Figure 4. l l

Like parts are identied by the same reference.

characters throughout the several views.

y In the construction shown in Figs. 1`to 3 inclusive, the lower unit is assembled in several separately die cast parts upon a conventional shaft housingy 1, such as is usually made of drawn tubing or the like. Insteadof terminating above the water line, as is now common practice in outboard motors designed for the higher speed ranges, this shaft housing is carried well below the water line to serve as a means of uniting the various die castings and to constitute a part of the so-called lower unit.

The gear casing 8 is a hollow die casting having an interior cavity at 3 for the bevel gears I0 and Il which, incidentally, may also be conveniently die cast. An integral sleeve extending rearwardly into the cavity 9 at l2 carries a conventional bushing i3 cast in place for the propeller shaft vertical driveshaft 20.

I4. An opening through the bow portion of the gear casing 8 for the core pin receives a plug Il which holds a thrust bearing.l When the gear casing iscompleted by the addition of the closure member hereinafter to be described, the bushed o bearings for the propeller shaft are aligned by reaming.

The stern side of the cavity 3 is closed by a closure member` I6 which-is provided internally with A'an integral sleeve at I1 intowhich is cast l0 a conventional bushing I8 for the rear end of the propeller shaft. The gear H is connected with the propeller shaft between sleeves i2 and I'l bya pin I3, and the gear i0 is suitably fixed to It 'willbe noted that the die cast gearpcasing unit 8 is integrally provided with a skeg at 2l which is suitably notched to receive closure member I6. At-its upper end the gear casing yunit 8 is provided integrally with a tubular' extension at 22 telescopically received into the end of the drive shaft housing 1 and shouldered at 23 to provide an abutment for the end of said housing. The lower end of the drive shaft 2li is journaled in bushing 24, and one or more screws at 25 pass through the drive shaft housing l and the sleevelike extension 22 of the .gear casing into the bushing 24 to hold the several parts in assembled relation.

An anti-cavitation plate exhaust discharge port and displacement pump are made to comprise a separate unit of the assembly.

Formed integrally with the forward portion 30 and the rearward portion 3i of the anti-cavitation plate, are semi-tubular clamp membersf32 and 33 held `by bolts 34 about the Vshaft housing 'l and preferably extended downwardly for strength to overlap the upper end of the tubular sleeve 22of the gear casing. y

'I'he pump cylinder 35 is cast integrally with the anti-cavitation plate portion 3| to extend 1ongitudinally thereof directly asternfromr the shaft housing 1 which is apertured to permitthe disv placement plunger 36 to enter the shaft. housing for engagement with a cam 31 on the drive shaft. 45 A spring at 38 engages the plunger to force it forwardly against the cam.

The plug 39 has a bail check valve to provide an inlet for the pump cylinder and an integrally cast duct 40 leads to the discharge pipe Il. 50 'I'he momentum of upward propulsion of the water is sufficient so that no outlet check valve is required for the pump.

A rearwardly directed discharge mouth 48 is likewise cast integrally with the anti-cavitation 55 plate section Il. It carries an integral sleeve at 46 to which the exhaust manifold 41 is connected.

Obviously the amount of metal required is very small as compared with other cast lower units. and a very strong structure is inherently produced with parts which are very light of weight per se.

'Ihe construction disclosed in Figs. 4, 5 and 6 presents a fully streamlined lower unit which may be die cast complete in two sections united on the longitudinal and vertical plane which includes the propeller shaft and drive shaft. These shafts are not illustrated, being similar to those disclosed in Fig. 1.

The two parts used in Figs. 4 to 6 are generically designated by reference characters 50 and 5i. 'Ihey are identical in outline and form and are complementary counterparts of each other. Each provides a smooth surfaced and externally streamlined wall portion at I3 reinforced externally by the longitudinally divided half M of an anticavitation plate and reinforced internally by a partition which separates a water passage 56 from the exhaust passage 51.

Due to the idle casting operation employed in the manufacture of the component parts 5l and 5|, it is possible to provide thickened metallic surfaces at 5l wherever the parts 50 and 5I are to be united. Each of the parts 50 and 5I carries its own portion of the skeg at fand 'the several holes clearly shown-in Figs are adapted to receive rivets whereby the component parts 50 and 5i are connected together in-pperative relation to `provide a closed lower unit..

Complementarysemi-circular openings in the component parts 50 and 5| provide a gear casing at 60, a propeller shaft bearing at 6 I a drain opening at' 82, awatex" inlet at 63, an exhaust outlet at 64,:4 d rive shaft and water circulation port at 65, and an exhaust connection at 66, and a drive shaft bearing at 61.

As compared with any other form of assembled lower unit of this general type, the die cast conr of dies, and strength and ease of manufacture.

1. An outboard motor lower unit comprising the combination with a gear casing section and an anti-cavitation plate section, of a tubular drive shaft housing connecting said sections, 'said sections having complementary sleeves telescopically engaging saidy housing in mutually overlapping relation.

2. In an outboard motor, a unit comprising an anti-cavitation plate integrally including a displacementv pump and cylinder, said plate having an aperture for a drive shaft housing to which said cylinder is open.

3. In an outboard motor, the rcombination withY ber complementary to the first member and cooperative therewith in fastening said ilrst member to said housing.

4. In an outboard motor lower unit, the combination of a gear casing having an integral upwardly projecting sleeve, of a shaft housing outwardly telescoped upon said sleeve, a bushing inwardly fitted to said sleeve, and securing means passing through said shaft housing, sleeve, and bushing, together with an anti-cavitation plate comprising complementary parts having integral semi-tubular portions telescopically engaging said housing externally thereof and in overlapping relation to said sleeve.

5. In an outboard motor, the combination with a drive shaft housing and an exhaust pipe spaced rearwardly therefromnof a clamp embracing said housing, a pump casing carried by said clamp and projecting rearwardly from said housing, an exhaust outlet fitting mechanically supported on said pump casing and providing a rearwardly directed exhaust gas outlet, said fitting being connected with said exhaust pipe whereby said pump casing provides mechanical support for said pipe from said housing.

6. In an outboard motor, the combination with a tubular shaft housing, lower unit and propeller, of a member connected with said shaft housin'g above said lower unit and including unitarily a pump casing projecting over the path of movement of the propeller, an inlet fitting communicating with the pump casing, an outlet passage provided with a water connection and communicating with the pump casing, and an elbow mounted on the pump casing and having an upwardly extending opening arranged to receive an exhaust pipe, and a rearwardly extending opening for the discharge of gases therefrom.

7. In an outboard motor,4 the combination with a shaft housing and a shaft therein provided with a cam, of a pump cylinder mounted on said shaft housing to project substantially at right angles therefrom, a displacement piston operable in said cylinder and arranged to be acted on by said cam, a downwardly opening valve iltting at the end of said cylinder and leading longitudinally along the top thereof toward said housing and provided with a pipe connection intermediate the ends of the cylinder, and an exhaust fitting ,comprising an elbow with an upwardly opening inlet and a horizontally opening outlet, said pump discharge passage being formed within said elbow.

8. In an outboard motor, the combination with a pump casing provided 'with a discharge passage communicating vertically with said casing and elbowed to provide a horizontal portion along the top of said casing, of an exhaust fitting integral with said pump casing and including an 

